More vehicle weight, size enhances safety in multiple vehicle crashes

Front-to-front crash tests, each involving a mini-car or a micro-car colliding with a mid-size model made by the same manufacturer, show how extra vehicle size and weight enhance occupant protection in collisions, the Insurance Institute for Highway Safety (IIHS) reports.
The IIHS recently conducted crash tests that don’t crash cars against a standard barrier, as is typically the case, but rather pit the test cars against one another at 40-mph speeds.
For example, the institute chose pairs of 2009 models from Daimler, Honda and Toyota because these automakers have micro and mini models that earn good frontal crashworthiness ratings, based on previous IIHS tests.
SUVs, pickup trucks and even large cars weren’t used because the choice of mid-size cars reveals how much influence some extra size and weight can have on crash outcomes, an IIHS release says.
While the Honda Fit, Smart Fortwo and Toyota Yaris are good performers in the frontal offset barrier test, all three are poor performers in the frontal collisions with mid-sized cars, the IIHS says.
“In a collision involving two vehicles that differ in size and weight, the people in the smaller, lighter vehicle will be at a disadvantage,” the release says. “The bigger heavier vehicle will push the smaller, lighter one backward during the impact. This means there will be less force on the occupants of the heavier vehicle and more on the people in the lighter vehicle.”
Greater force means greater risk, so the likelihood of injury goes up in the smaller lighter vehicle.
The death rate in mini-cars between one and three years old in multiple vehicle crashes during 2007 was almost twice as high as the rate in very large cars, the institute notes.